Circuit breaker



H. D. DORFMAN 1,966,286

CIRCUIT BREAKER July l0, 1934.

Original Filed Sept. 6,'1930 ATTO'RNEY Patented July 10, 1934 PATENTorrlcE messes cracvrr Bamm Hiller D. Do

Mannelli. om, 'mimma riman, Westinghouse Electric & Manuiact Company. acorporation oi Pennsy, lvaniawm8 Application September 6, 1930. SerialNo. 480,096

- Benewed September 16, 1983 21 Claims.

My invention relates to circuit breakers and particularly to circuitbreakers to be mounted in sheet-metal enclosures for controllinglighting and motor. circuits.

5 An object of my invention is to provide a multipole circuit breakerwherein a current-responsive trip mechanism is associated with at leasttwo of the poles of the circuit, and wherein the trip mechanismreleasably retains a single latch element l0 of the circuit breaker inclosed position, thereby rendering the circuit breaker responsive tocurrent conditions in either of the two poles of the circuit.

A further object of my invention is to provide 'l5 a simplecurrent-responsive tripping element that may be applied to multiplecircuit breakers of standard construction, and which may be detachablymounted upon the circuit breaker base,

in order to permit of interchange of current-re- 80 sponsive elementshaving ditlerent operating characteristics.

A further object of my invention is to provide a trip mechanism for acircuit breaker wherein a plurality of cooperating cam elements serve tojointly and releasably retain the circuit breaker from being tripped toopen position, and wherein the cam members are retained in latchingposition by separate independently operable currentresponsive elements.

A further object of my invention is to provide a trip mechanism for acircuit breaker that comprises a minimum number of parts which areassembled in compact relation.

These and other objects, that will be made apparent throughout thefurther description of my invention, are attained by means of thecircuit-breaker apparatus hereinafter described, and illustrated in theaccompanying drawing, wherein Figure 1 is an elevational view, partiallyin section, of a circuit breaker embodying features of my invention;

Fig. 2 is an enlarged front elevational view of the current-responsivetrip mechanism shown in Fig. 1;

Fig. 3 is an enlarged end elevation of the trip mechanism shown in Fig.2, and

Fig. 4 is a side elevational view of a cam.

Referring to the drawing, the circuit breaker comprises an insulatingbase 7 upon which is mounted a sheet-metal-frame structure 8 to supportthe circuit-breaker unit which is similar in construction to thatminutely described in Patent No. 1,794,901 of Oliver S. Jenningsassigned to the assignee of this application.

66 Briefly, the circuit breaker unit comprises the (CL 20o-116) frame 8upon which a cradle 9 is pivoted for rotation about the pivot pin 11. Anoperating arm 12, having a handle 13, is pivoted for rotation about thepivot pin 14, and a pair of tension springs 15 are attached, at theirouter ends, to 00 the arm 12 and, at their inner ends, to the knee pivot16 of a pair of toggle links 17 and 18 which serve to operate a pivotedswitch arm 19 that is mounted to oscillate about a pivot shaft 21mounted on the frame 8, the link 17 being pivoted to 65 the arm 19 bythe pivot shaft 22. and the toggle link 18 being pivotally connected tothe cradle 9 at the point 23 in the apex of a notch 24 of V- shape inthe cradle 9.

The contact arm 19 carries a flexible leaf spring 70 25, upon the freeend of which is mounted a movable contact 26 that ls adapted to engage astationary contact 27.

'lhe cradle 9 is releasably retained in the closed position shown inFig. 1 by means of a latch arm 75 that will be hereinafter described.The circuitbreaker apparatus may be designated as of the tumbler typewherein an overcenter spring serves to move the contact to open and toclosed positions. As shown in Fig. 1, the contact 26 is in 80 openposition and is moved to closed position with a snap action when theoperating handle 13 has been moved clockwise a sumcient distance to movethe outer ends of the springs l5 past a center line traversing the pivotshaft 16 and the point 23 re- 85 ferred to above. When this movement ofthe operating handle 13 has been accomplished, the springs 15 will snapthe lower pivot shaft 16 toward the right and straighten the togglelinks 17 and 18 for forcing the contact 26 into the closed 90 position.

When it is desired to move the switch to open position manually, theoperating handle 13 is moved to the left or in a counter-clockwisedirection, and, when the springs 15 again pass over 95 theabove-mentioned center line, the toggle will be broken with a snapaction and cause the contact 26 to quickly separate from the contact 27.

In the event of an overload or a short-circuit condition, the latch armis released, in a manner to be hereinafter described, and the springs15, which are in an extended stressed condition when the circuit breakercontact is closed, cause the cradle 9 to turn in the clockwisedirection, which movement causes breaking of the toggle and thesubsequent rapid separation of the contact 26 from the contact 27.

This form of circuit-breaker apparatus is completely described in theabove-mentioned patent, and it is believed that no further explanationof the construction and operation of the circuit breaker is necessaryfor the purpose of this application, which is concerned more with theparticular form of current-responsive releasing apparatus suitable for amulti-pole circuit breaker.

However, it is to be understood that the present form of circuitbreaker, as disclosed in Fig. 1, is of the two-pole type in which theoperating mechanism above described is employed for operating twocontact arms 19 that are connected at their inner ends by means of aninsulating cross bar 29.

Referring particularly to Figs. 2 and 3, the current-responsive trippingor releasing device comprises a metal frame 31 of U-shape that issecured upon an insulating standard 32 that is integral with theinsulating base 7, by means of screws 33. A pair of rotatable cams 34and 35 are mounted between the side flanges 36 of the frame 31 forrotation about pivot pins 3'?, the adjacent faces of the cams beingprovided with two fiat angularly disposed portions 38 and 39, asindicated in Fig. 4.

The cams 34 and 35 are normally biased in a counter-clockwise andclockwise direction, respectively, by a helical spring 41 that serves tonormally, yieldingly retain the cams in their open, latch-receivingposition.

The cradle 9 of the circuit breaker is provided with a latch arm 42 thatis moved into the space between the cam faces when the circuit breakeris moved to closed or operative position wherein the cradle occupies itsreset position shown in Fig. 1, the inner edge of the latch arm 42 beingadapted to engage overlapping resetting arms 43 on the cams 34 and 35,which move the cams against the tension of the spring 41 into thelocking positions, as indicated in Fig. 2, where they are releasablyretained by bimetal elements 44 and 45, respectively, that are of theusual U-shape construction well known in the art. The movable outer endsof the bimetal elements 44 and 45 are provided with insulated latchclips 46 that engage shoulders 47 on the cams 34 and 35.

It will be noted that the space40 between the closest cam surfaces ofthe cams, when the cams are in locking positions, is of less width thanthe thickness of the latch arm 42, and, consequently, the latch arm isretained in closed position so long as the cams are prevented fromrotating in opposite directions. However, should either one of the camsbe released by the outward movement of either of the bimetal elements 44and 45, the spring 41 immediately causes rotation of the cam, whichresults in widening of the space between the cam faces and consequentrelease of the latch arm 42 which is of such yielding construction thatit may be deflected laterally a sufficient distance to clear the camthat remains stationary.

It will be understood that the bimetal element is connected in serieswith its respective contact arm and is heated by current flowing in thecircuit controlled by the contact arm 19 and is, therefore, responsiveto current conditions in that circuit. In the event of an overload orshort-circuit condition, the bimetal element deects laterally andreleases its respective cam, thus causing opening movement of thecircuit breaker in a well known manner.

Resetting movement of the circuit breaker causes resetting of the cam,and it will be noted that the anges 36 of the frame 3l are provided withalined notches 50 o! U-shape, which permit of sufficient inward movementof the latch arm 42 to accomplish resetting of the cams in the positionshown in Fig. 2.

By reference to Fig. 1, it will be seen that the bimetal elements 44 and45 are connected in series with the contacts 26 and 27, the circuitbeing as follows: the live feed conductor 48 is attached to the terminal49, and current passes from the terminal 49, through conductor strap 51,screw 52, conductor strap 53, screw 54,'contact 27, movable contact 26,flexible spring contact arm 25, flexible conductor 55, terminal 56,screw 57, conductor strap 58, screw 59, terminal 61, one of the bimetalelements 44 and 45, element terminal 62, screw 63, conductor strap 64,screw 65, conductor strap 66 and terminal screw 67, to load conductor68.

I have thus provided a simple, inexpensive and compact form ofcurrent-responsive trip mechanism for a multi-pole circuit breaker thatmay be readily applied to circuit breakers of standard construction, andI have provided a trip-mechanism construction wherein the operatingcharacteristics of the circuit breaker with which it is associated maybe varied by interchanging current-responsive units having differentoperating characteristics.

While I have illustrated but one embodiment of my invention, it will beapparent to those skilled in the art that various changes,modifications, substitutions, additions and omissions may be made in theapparatus illustrated without departing from the spirit and scope of myinvention, as set forth in the appended claims.

I claim as my invention:

1. A trip device for a circuit breaker comprising a pair ofindependently operable members that. when in predetermined relativepositions, jointly and rcleasably retain an element which when releasedcauses movement of the circuit breaker to open position, means wherebysaid members are moved to said positions when the circuit breaker ismoved to closed position, and independent current-responsive means forreleasably retaining the said members in retaining position.

2. A trip device for a circuit breaker comprising a pair ofindependently movable cam members that, when in predetermined relativepositions, jointly and releasably retain an element which when releasedcauses movement of the circuit breaker to open position, means on thecams whereby the cams are moved by the circuit A breaker to the saidpositions when the latter is moved to the reset or closed position, andindependently operable current-responsive means for releasably retainingthe cams in the said positions.

3. A trip device for a circuit breaker comprising a pair ofindependently movable carn members that, when in predetermined relativepositions, jointly and releasably retain an element which when releasedcauses movement of the circuit breaker to open position, means on thecams whereby the cams are -moved by the circuit breaker to the saidpositions when the latter is moved to the reset or closed position,means for biasing the cams out of the said predetermined positionstoward releasing position, and independently operable current-responsivemeans for releasably retaining the cams in the said predeterminedpositions.

4. A trip device for a circuit breaker having a latch arm, said tripdevice comprising a pair of independently movable cams pivotally mountedupon separate substantially parallel axes and having their peripheralcam faces adjacent to one another, and between which the 1,900,2s0 i 3latch arm moves when the circuit breaker is latched position -forreturning the trip members moved to the reset or closed position, thesaid to their non-tripping position.

cam faces having cooperating portions which, when in predeterminedrelation, jointly prevent release of the latch arm and which @moved toreleasing position by the latch arm when rotation of the cams ispermitted, and independently operable current-responsive means forreleasably preventing rotation of the cams.

5,. A trip device for a multi-pole circuit breaker including means forretaining the contacts of all o! the poles of the circuit breaker frombeing tripped to open position, said retaining means being releasablefor causing the opening of said contacts, a separate current responsivedevice for each of a plurality of poles of said circuit breaker, anindependently operable trip member for each of said current responsivedevices and operable thereby to tripping position inresponse to apredetermined current ilow in said device, the movement of any one ofsaid trip members causing the release of said retaining means to openthe contacts of the circuit breaker, and means actuated by movement ofthe circuit breaker for resetting all of said trip members tonontripping position.

6. A trip device for a multi-pole circuit breaker including a releasablelatch arm upon movement of which the contacts of the several poles ofthe circuit breaker are moved to open position, a separate independentlyoperable trip member for earch of a plurality of poles of the circuitbreaker normally biased toward tripping position and any one ot whichwhen released causes the release of said latch arm, a separateindependently operable current responsive trip element associated witheach of said two or more poles of the circuit breaker for releasablyretaining said trip members in non-tripping position, and means forreturning the trip members to their non-tripping position before thecontacts are reclosed after being tripped.

7. In a multi-pole circuit breaker an operating member for opening andclosing the contacts of all the poles of said circuit breaker, means foropening said contacts irrespective of the position of said operatingmember and retaining means for holding said contacts closed when saidoperating member is in closed position, a separate current responsiveelement for each of a plurality of poles of the circuit breaker, aseparate pivoted trip member biased to tripping position and held innon-tripping pomtion by each of said current responsive elements, themovement of any one of said trip members causing the release of saidretaining means to open the contacts of the circuit breaker and meansactuated by movement of said operating member for retaining each of saidtrip members to non-tripping position where it is held by said currentresponsive elements.

8. A trip device for a multi-pole circuit breaker including a latch armwhich when released causes movement of the contacts of the several polesof the circuit breaker to open position, a separate independentlyoperable trip member for each of a plurality of poles of the circuitbreaker and any one of which when actuated causes the re-` lease of saidlatch arm, a separate independently operable current responsive tripelement associated with each of said two or more poles of the circuitbreaker for causing the actuation of said trip members to trippingposition, and means actuated by movement of said latch arm to 9. In amulti-pole circuit interrupter, contact members for each pole thereof, amember movable to cause the opening of all of said contact members,means for causing movement of said movable member including a separatecurrent responsive device for each of a plurality of poles of thecircuit interrupter, a plurality of trip members each controlled by oneof said current responsive devices and movable to tripped positionirrespective of the current through any other of said current responsivedevices and said movement `to tripped position of any one of said tripmembers causing movement of said movable member to open all of saidcontact members, and means actuated by movement of the circuitinterrupter for resetting any of said trip members that have moved totripped position.

10. In a multi-pole circuit interrupter, contact members for each polethereof, a member movable to cause the opening of all of said contactmembers, a spring biasing said member to cause said movement, aplurality of trip members jointly holding said movable member againstthe bias of said spring, a plurality of current responsive elementselectrically connected in different poles of the circuit interrupter,means biasing said trip members into engagement with said currentresponsive elements, and each of said trip members being releasable tocause release of said movable member upon movement of its currentresponsive element independently of movement of any other of saidcurrent responsive elements.

11. In a multi-pole circuit interrupter, contact members for each polethereof, a member movable to cause the opening of all of said contactmembers, a spring biasing said member to cause said movement, aplurality of trip members jointly holding'said movable member againstthe bias of said spring, a plurality of current responsive elementselectrically connected in different polesfof the circuit interrupter, asingle spring biasing said trip members into engagement with saidcurrent responsive elements,` and each of said trip mem- -bers beingreleasable to cause release of said movable member upon movement of itscurrent responsive element independently of movement of any other ofsaid current responsive elements and means for moving said movablemember upon actuation of the circuit interrupter after being tripped,said movement of the movable member returning said trip members intoengagement with said current responsive elements.

12. In a circuit interrupter, a contact member movable to open and closethe circuit, a pivoted operating member for normally moving said contactmember to open and close the circuit, a spring having its line of actionmovable across the pivot of said operating member for actuating it witha snap action to both open and closed positions, a handle for actuatingsaid spring, means for causing the opening of said contact member inresponse to predetermined conditions including a trip member, a secondspring biasing said trip member to trippedposition, the strain of saidsecond spring remaining substantially constant during movement of saidhandle when normally moving said contact member` to open and close thecircuit, a current responsive element releasably preventing movement ofsaid trip member by said second spring to tripped position, and saidtrip member when released moving under action of said second spring andthereby causing movement of said pivoted operating member to 'cause iloopening movement of said contact member irrespective ofthe position ofsaid handle.

13. In a circuit interrupter, a contact member movable to open and closethe circuit, a pivoted operating member for normally moving said contactmember to open and close the circuit, a spring having its line of actionmovable across the pivot of said operating member for actuating it witha snap action to both open and closed positions, a handle movablebetween an on and an on position for actuating said spring, means forcausing the opening of said contact member in response to predeterminedconditions including a trip member, a second spring biasing said tripmember to tripped position, a current responsive element releasablypreventing movement of said trip member to tripped position, and saidtrip member when released moving under action of said second spring andthereby causing movement of said pivoted operating member to `causeopening movement of said contact member irrespective of the position ofsaid handle, and rigid means for transmitting motion of said handlemember to said trip member to positively reset it and stress said secondspring upon movement of said handle toward off position after thecircuit interrupter has been tripped.

14. In a multi-pole circuit breaker, a contact member for each of aplurality yof said poles, said contact members being movable betweenanopen and a closed position, spring means, an actuating member movablefor actuating a plurality of said contact members, said actuating memberstressing said spring means during a portion of its movement andthereafter causing said spring means to move a plurality of said contactmembers to closed position with a snap action, tripping means forcausing opening of a plurality of said contact members, a second springmeans for biasing said tripping means to tripped position, currentresponsive means releasably retaining said tripping means againstmovement, said current responsive means being responsive topredetermined conditions in a plurality of said poles and causingmovement -of said tripping means by said second spring means for causingmovement of a plurality of said contact members to open position uponthe occurrence of said predetermined conditions in one pole.

l5. In a multi-pole circuit breaker, a contact member for each of aplurality of said poles, said contact members being movable between anopen and a closed position, spring means, an actuating member movablefor actuating a plurality of said contact members, said actuating memberstressing said spring means during a portion of its movement andthereafter causing said spring means to move a plurality of said contactmembers to closed position with a snap action, tripping means forcausing opening of a plurality of said contact members, a second springmeans for biasing said tripping means to tripped position, currentresponsive means releasably retaining said tripping means againstmovement, said current responsive means being responsive topredetermined conditions in a plurality of said poles and causingmovement of said tripping means by said second spring means for causingmovement of a plurality of said contact members to open position uponthe occurrence of said predetermined conditions in one pole, and saidtripping means causing opening of said contact member irrespective ofthe position in which said actuating member may be held, and saidactuating member being connected to reset said tripping means and tore-stress said second spring means upon movement of the actuating memberafter said tripping means has caused opening of the contact members. i

16. In a multi-pole circuit interrupter, a contact member for each of aplurality of poles thereof, a member movable to cause opening of aplurality of said contact members. a spring for biasing said member tocause said movement, a plurality of trip members each supplying onecomponent of a force holding said movable member against the bias ofsaid spring and the removal of the component o! said force supplied byany one of said trip members causing movement of said member to causeopening of said contact members, and a current responsive element foreach of a plurality oi said poles and each of said current responsiveelements causing removal of the component of force exerted by one ofsaid trip members upon the occurrence of predetermined conditions in onepole of the circuit interrupter.

17. In a multi-pole circuit interrupter, a contact member for each of aplurality of poles thereof, a member movable to cause opening of aplurality of said contact members, a spring for biasing said member tocause said movement, a plurality of trip members each supplying onecomponent of a force holding said movable member against the bias ofsaid spring and the removal of the component of said force supplied byany one of said trip members causing movement of said member to causeopening of said contact members, means for biasing said trip members tomove to a position where said components of force are removed, and acurrent responsive element for each of said trip members for controllingtheir movement by said biasing means.

18. In a circuit interrupter, a contact member movable to open and closethe circuit, a pivoted operating member for normally moving said contactmember to open and close the circuit, a spring having its line of actionmovable across the pivot of said operating member for actuating it witha snap-action to both open and closed positions, a handle movablebetween an on and an off position for actuating said spring, means forcausing the opening of said contact member in response to predeterminedconditions vincluding a trip member, a second spring biasing said tripmember to tripped position, the strain of said second spring remainingsubstantially constant during movement of said handle when normallymoving said contact member to open and close the circuit, a currentresponsive element releasably preventing movement of said trip member bysaid second spring to tripped position, said trip member when releasedmoving under action of said second spring and causing movement of saidpivoted operatingI member to cause opening movement of said contactmember irrespective of the position of said handle, and rigid means fortransmitting motion of said handle member to said trip member to resetit and stress said second spring upon movement of said handle toward ofiposition after the circuit interrupter has been tripped.

19. In a multi-pole circuit breaker, a contact member for each of aplurality of said poles, said contact members being movable between anopen and a closed position, spring means, an actuating member movablefor actuating a plurality of said contact members, said actuatingmember'stressing said spring means during a portion of its movement andthereafter causing said spring means to move a plurality of said contactmein# bers to closed position with a snap action, tripping means forcausing opening of a plurality of said contact members, a second springmeans for biasing said tripping means to tripped position, the strainof-said second vspring remaining substantially constant during movementoi' said actuating member when normally moving said plurality oi'contact members to open and closed positions, current responsive meansreleasably retaining said tripping means against movement by said secondspring, said current responsive means being responsive to predeterminedconditions in a plurality of said poles and causing movement of saidtripping means by said second spring means i'or causing movement of aplurality of said contact members to open position upon the occurrenceof said predetermined conditions in one pole.

20. In a multi-pole circuit breaker, a contact member for each o1 a.plurality oi' said poles, said contact members being movable between anopen and a closed position, spring means, an actuating member movablefor actuating a plurality of said contact members, said actuating memberstressing said spring means during a portion of its movement andthereafter causing 4said spring means to move a plurality of saidcontact members to closed position with a snap action, tripping meansfor causing opening oi a plurality of said contact members, a secondspring means for biasing said tripping means to tripped position,current responsive means releasably retaining said tripping meansagainst movement, said current responsive means being responsive topredetermined conditions in a plurality of said poles and causingmovement of said tripping means by said second spring means for causingmovement o1 a plurality of said contact members to open position uponthe occurrence of said predetermined conditions in one pole, and saidtripping means causing opening of said contact S member. irrespective ofthe position in which said actua member may be held, and rigid means fortransmitting motion oi' said actuating niember to reset said secondspring means upon movement of the actuating member after said trippingmeans has caused opening of the contact members.

21. In a multi-pole circuit breaker, a contact member for each of aplurality oi' said poles, said contact members being movable between anOpen and a closedposition, spring means, an actuating member movable foractuating a plurality of said contact members, said actuating memberstressing said spring means during a portion of its movement andthereafter causing said spring means to move a plurality of said contactmembers to closed position with a snap action, tripping means forcausing opening of a plurality oi' said contact members, a second springsaid tripping means and to re-stress ing substantially constant duringmovement of I I said actuating member when normally moving saidplurality of contact members to open and closed positions, currentresponsive means releasably retaining said tripping means againstmovement by said second spring, said current responsive means beingresponsive to predetermined conditions in a plurality of said poles andcausing movement of said tripping means by said4 second spring means forcausing movement of a g contact members to open position upon theoccurrence of said predetermined conditions in one pole, and saidtripping means causing opening of said contact member. irre v saidactuating',

spective of the position in which member may be held, and rigid meansfor transmitting motion of said actuating member to reset said trippingmeans and to re-stress said second spring means upon movement of theactuatingmember after said tripping means has caused opening oi thecontact members.

HILLER D. DORFMAN.

CERTIFICATE or CORRECTION.

Patent No. l, 966, 286.

July l0, 1934.

HILLER D. DORFMAN.

claim 7, for "retaining" thecase in the Paieni Office.

Signed and sealed this lltii (Seal) printed specificiirion of the Page3, line 58-59,

said Leiters Patent should conform to Ihe record of day of September, A.D. 1934.

' `l Leslie Frazer Acting Commissioner of Patents.

Iso

DISCLAIMER 1,966,286.Hler D. Dorfman, Mansfield, Ohio. CIRCUIT Bnmllxmn.Patent dated July 10, 1934. Disclaimer filed March 20, 1941, by theassignee, Westinghouse Electra: cf: Manufacturing Company. Hereb entersthis disclaimer to claims 5, 6, and 9 of the patent.

[ cal Gazette April 8, 1941.]

